digestion in the mouth

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What is the primary reason why enzymes can react with food molecules in saliva?

Because the water in saliva helps dissolve foods (correct)
Because the mucus in saliva lubricates food
Because the lysozyme in saliva kills bacteria
Because the bicarbonate and phosphate ions in saliva buffer acidic foods

What is the average daily secretion of saliva?

5 liters
2 liters
0.5 liters
1 liter (correct)

Which ion has a higher concentration in saliva compared to blood plasma?

Na+
Ca2+
Cl-
K+ (correct)

What is the primary function of lysozyme in saliva?

To kill bacteria (B) Signup and view all the answers

What is the tonicity of saliva compared to blood plasma?

Hypotonic (C) Signup and view all the answers

What is the primary function of salivary amylase in saliva?

To begin the digestion of carbohydrates (A) Signup and view all the answers

What is the primary reason for the similarity in composition between saliva at the highest flow rates and blood plasma?

Decreased time for ion absorption and secretion by the ductal cells (A) Signup and view all the answers

Which electrolyte is NOT affected by the 'contact time' explanation of saliva composition?

Bicarbonate (C) Signup and view all the answers

What is the result of the slow transit of saliva through the ducts at the lowest flow rates?

A significant change in the concentrations of Na+, Cl-, K+, and bicarbonate (D) Signup and view all the answers

What is the primary site of ion absorption and secretion that affects the composition of saliva?

Ductal cells (D) Signup and view all the answers

Which of the following best describes the composition of saliva at the lowest flow rates?

Shows the greatest difference in ionic composition compared to blood plasma and the initial saliva (B) Signup and view all the answers

What is the effect of fast transit of saliva through the ducts on the concentration of Na+ and Cl-?

Only a small change in the concentration of Na+ and Cl- (A) Signup and view all the answers

What is the expected relationship between saliva flow rate and bicarbonate concentration in saliva based on secretion by ductal cells?

The concentration of bicarbonate in saliva is highest at the slow saliva flow rates. (A) Signup and view all the answers

What is the actual relationship between saliva flow rate and bicarbonate concentration in saliva?

The concentration of bicarbonate in saliva increases as the flow rate increases. (D) Signup and view all the answers

Which type of control does not play a role in the regulation of secretion by the salivary glands?

Hormonal control (C) Signup and view all the answers

What is the effect of sympathetic stimulation on the composition of saliva?

It makes the saliva more viscous. (D) Signup and view all the answers

What is the primary mechanism of control of saliva secretion?

Autonomic control (D) Signup and view all the answers

What is the effect of parasympathetic stimulation on the composition of saliva?

It makes the saliva more watery. (B) Signup and view all the answers

What is the primary reason for increased blood flow to the salivary glands during parasympathetic stimulation?

Formation of bradykinin (C) Signup and view all the answers

Which cranial nerves are responsible for transmitting parasympathetic signals to the salivary glands?

Facial (VII) and Glossopharyngeal (IX) nerves (D) Signup and view all the answers

What is the role of the salivatory nuclei in the brain stem?

To integrate signals from the taste buds and send them to the salivary glands (C) Signup and view all the answers

What is the primary function of lingual lipase in the stomach?

To break down dietary lipids into fatty acids and glycerol (A) Signup and view all the answers

What is the result of the increased surface area of food particles exposed to enzymes during digestion?

Faster digestion of food particles (A) Signup and view all the answers

What is the effect of sympathetic stimulation on the salivary glands?

Vasoconstriction and decreased secretion of saliva (D) Signup and view all the answers

What is the primary function of chewing in the mouth?

To reduce the size of food particles and mix them with saliva (A) Signup and view all the answers

What is the origin of the sympathetic nerves that innervate the salivary glands?

Th1-Th3 segments of the spinal cord (C) Signup and view all the answers

What is the primary stimulus for secretion of saliva in response to food?

Chemicals present in the food stimulating the taste buds (A) Signup and view all the answers

Which type of teeth is responsible for cutting the food?

Incisors (A) Signup and view all the answers

What is the role of the chewing muscles in the digestion process?

To facilitate chewing and grinding of food in the mouth (A) Signup and view all the answers

What is the duration of salivary amylase activity on starch after swallowing?

About 1 hour (C) Signup and view all the answers